The OSUCCC Transgenic Animal Shared Resource (TASR), rated as "outstanding" in the 1999 review, provides support in all areas of preimplantation mouse embryo development and manipulation, including transgenic, embryonic stem (ES) cell technologies, mouse embryo cryopreservation and rederivation. The shared resource serves OSUCCC investigators from two different operational sites to accommodate the needs of investigators encompassing the entire Health Sciences Campus at OSU. The TASR component at the Center for Molecular Neurobiology (CMN) operates in Rightmire Hall on the campus of OSU and is under the direction of Anthony P. Young, Ph.D. The TASR component at Children's Research Institute (CRI) is approximately 5 miles from the main OSU campus and is directed by Michael L. Robinson, Ph.D. The TASR provides common basic services such as pronuclear and blastocyst injections;embryonic stem cell (ES cell) storage, culture, electroporation and selection; mouse strain rederivation and cryopreservation, as well as more specialized services including embryo to embryo and embryo to ES cell aggregation and tetraploid embryo production. The TASR also provides training opportunities in embryonic stem cell techniques and maintenance of unique mouse models for OSUCCC investigators. Each branch facility is equipped with resources including multiple inverted microscopes with micromanipulators for microinjection, microforges, micropipette pullers, C02 incubators, refrigerators/freezers, and other specialized equipment. In addition to the in-house generated mouse strains, the facility also houses multiple mutant strains of mice for onsite access to the investigators. The TASR directors provide consultation with OSUCCC investigators at all stages of planning and operation of projects involving genetically engineered mice. This includes advice on transgenic and targeting strategies, vectors and screening procedures. In addition, the personnel of the OSUCCC TASR organize workshops, develop protocols, and provide assistance with analyses of genetically engineered mice. Of 154 total microinjection (transgenic) constructs, producing 743 transgenic founders, over 85% were from OSUCCC members. As OSUCCC increases its focus in cancer genetics and experimental therapeutics the TASR will increase its development of mouse models of cancer. The TASR expends approximately 82% of its total effort on projects supported by 49 OSUCCC members, yet requests only 38% of its budget from CCSG funding.